Can you post a screenshot. Because it is hard to imagine that it is working in some parts but not others as the code is simply saying ... when blizz says to display the extra action bar display it ... the bug with hiding the main bar at the same time would affect it every time not just on one element.

Have the extraactionbutton1 macro ready on one of your other bars just in case it happens again.

Has someone else seen this happen? I haven't done that instance myself so cannot say either way but code wise it just isn't possible to have this happen in this way.

Looking at a screenshot here ( http://i46.tinypic.com/9a2vdf.jpg ) that is said to be from the same boss fight it shows the override bar (which overrides the main action bar ) and adds 3 actions for you to use. Now, the question is, do you get these spells appear on the action bar and does the extra action button then appear ( or supposed to ) at the same time?

If that is the case unfortunately there is no quest that has that combination to be able to test it outside of the dungeon run. So, to know what is supposed to happen one would have to run it without nUI running to see how blizzard has it designed to run like and then try and mimic it.

Looking elsewhere around the internet it seems other button addons have a similar problem and people are reduced to using the extra action button macro to resolve it. Perhaps another instance where the situation isn't being flagged properly for us to display things right. EG. I am displaying the override bar ( a 6 button max replacement action bar ), the playeralt bar ( an extra frame ) but when I feel like it I will be displaying the extra action button for you to click ( a single button ) as and when required.

The fix in 5.06.28 stopped the main bar from changing when the extra button is displayed but it does change whenever blizzard tells us the override bar is being displayed as it is supposed to replace the main action bar with actions you are supposed to use at that time.

So, what we need to have done if anyone ever gets to go in there is ... :

1. A screenshot of what blizzard ( without an action bar addon being used like bartender/nUI etc ) is doing

2. A screenshot of what nUI is doing at the same time. Have the extra action button macro ready to use so that at least you don't wipe the group ( if that is the end result ).

There is a chance that one of the other frames that coincidently gets displayed at the same time is hiding the button for you due to the frames location. But again until we see a screenshot we can't confirm what is happening to try and locate a fix for it.